The Toyota dealer determined a 2005 Prius had a slow refrigerant leak likely in the compressor. To replace the compressor would be $800 and doing that repair on a car with 250k miles doesn’t make sense. The leak was small enough that charging the refrigerant would last over 6 months but costs $100+ from a dealer or garage. Charging does not require special gauges as there are filling solutions with built-in gauges available for less than $40. In this case, one bottle of refrigerant will do multiple charges.
- Note the outside temperature and turn the car on with the AC on High
- Locate the grey Low pressure port for the AC marked with an L and remove the cap
- Rotate the bezel on the gauge to the outside temperature. This will adjust how much you will add.
- Attach the filling hose. It just snaps on.
- Depress the trigger for 5 seconds. Shake and rotate the refrigerant so it flows in. Release the trigger and check the pressure. If more is needed, repeat.
When you go in the running car, the AC should feel cold. If not, something else is wrong with the AC system. These steps work on most modern cars.
Unlike Freon, modern refrigerants don’t hurt the ozone layer. Unfortunately, refrigerants like R-134A impact global warming. Refrigerants contribute less than 1% of the overall impact to global warming but R-134a HFC refrigerant has an impact 1,430 higher than that of carbon dioxide. Releasing (by not fixing the leak) 10 ounces (1/2 a can) of refrigerant has a greenhouse impact of releasing CO2 from burning a 100 gallons of gasoline.